Improvement in pneumatic springs for cars



UNITED STATES s PATENT OFFICE,

JOHN MERLETT, OF BOUNDBROOK, NE\V JERSEY.

,IMPROVEMENT IN PNEUMATIC SPRINGS FOR CARS.

Specilication forming part ot' Letters latent bo. 51,956, dated 'January ff, li; tinted-atm'.

I v Deceuibtr 2s, 1.5115.

To all A107mm fit may concern:

Be it known that' I, JOHN MERLETT, of Boundbrook, in the county of Somerset and State ot'New Jersey, have invented a new and useful lfniprovement in lneumatic Springs for Railway-Cars and other uses; and I do hereby declare that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming part of this specification, in which- Figure l is a vertical central section of my improved spring. Fig. 2 isa horizontal section of the same through the linea, Fig. l.

Similar letters ot' reference indicate corresponding parts in both figures.

This invention consists in au improved construction ot" a pneumatic spring, whereby I Yprevent the escape of air by the interpositiou of a liquid between the cushion ot' air and the plunger or headot the spring'.

To enablel others to construct and apply my invention, 'l will proceed to describe it with reference to the-drawin gs.

A and A are two cylinders, cast together or otherwise connected at the top, and firmly secured by bolts ff to a baseplate, E, with vau interposed packing, y, which forms a perfectly tight `joint. Communication is formed to and from the inner cylinder, A', and the annular chamberA2, between the inner and outer cylinders, by means of openings a a in the lower part of the inner cylinder. The inner cylinder is bored truly for the reception of a plunger, B, to the upper part of which is attached a cylindrical cap, bl, which lits easily over the exterior of the cylinder A, to form a guide to the plunger anda bearing for the car- `body or other b ody to be supported by the spring. This cap has two or inorelugs, d, projecting from the, lower part ot' its exterior, and bolts c c areinsertcd through holes in these lugs and screwed into the llange at the bottom of the cylinder A. The heads c' c ol' these bolts serve as guards to prevent the cap b3 from being pushed off the cylinder A by the pressure of the -air in the chamber A2 acting against tlie bottom ofthe plunger when there is no load ou the cap b3. lIoles G G are provided in the cap b3, to prevent any cushioning 0f air between the head ofthe cylinders A A' and the said cap.

The plunger l5 is fitted around its lower part with packing 11,01'1 any suitable character. The packing represented in this place is an ordinary water-packing, ol' leather, secured in \place by a broad-headed bolt, 13', passing` -through the center of the plunger; and in order to keep this packing tight against the bore of' the cylinder' A while the plunger is moving upward, a coiled or volute spring, b2, like a clock-spring, is placed between thesaid packing and the head ofthe bolt B. l

A stop cock or nozzle, C,is inserted into the lower part ot' the cylinder A for the attachment ot' the eduction-pipe of a pump, by which pressure greater than that of the atmosphere, such air rising above the water or otherliquid der A with a check-valve,which retains the pressure within the chamber A2 until the cock is closed or a cap put onjthe nozzle. Before putting the plunger B into ythe cylinder A a sullicient quantity of water or other liquid is poured into the said cylinder to keep the said cylinder filled up' to the plunger, and

to allow enough to be retained in the annular chamber A2 to cover the holes a a in the highest position to which the plunger is permitted to rise. After the plunger has been put in and secured to the `guard-bolts c c the air is pumped into the chamber Alto a suitable pressure to enable it to sustain the weight to be supported by the spring. l

In applying my spring to use the base-plate may be placed upon or against the axle-box or other support, and the truck, car, or other I body to be supported is placed upon the cap b3, or /this position may be reversed. 4ln the concussions to whiclnthc spring is subject the plunger works freely in the cylinderA and the water or liquid passes freely to and i'ro between the cylinder A andannular chain` ber A2, keeping` the air-cushion always separate'd from the plungerand from-.the point g,

and sealing` both the said joint and the plunger against leakage ot' air.

Air or liquid maybe pumped into the chamber A2 at. any time, lto increase the tension or resisting power of' .the sprin g whenever, from air is forced into the annular chamber A2 ata contained in the. lower part of' the said chamV ber to formv the elastic cushion or spring. This cock or nozzle is fitted inside the cyl1n,

las alcohol, which will not be liable to freeze,

must be used. l

What I claim as my invention, and desire to secure by Letters Patent, is-

l. The construction of a-pneumati'c spring with an annular air-chamber, A2, surrounding and communicating` at the bottom with the cylinder A, in which the plunger B or its equivalent Works, and separated from lthe said plunger or its equivalent by an interposed column of liquid, substantially as and for the purpose herein-specified.

2.I rEhe cap b3, attached to the plunger Py and combined with the external cylinder, Anf

of the annular air-chamber, to form a guide for the said plunger, substantially as herein specified.

JNO. MERLETT. Witnesses:

I. W. CooMBs, G. XV. tEED. 

